Multistakeholder forums (MSF) have gained global popularity as an innovative institutional reform in the governance of land use decision-making, including territorial planning processes. The idea, or ideal, is to bring together diverse actors to advance the paradigms of "good governance" and "sustainable development". However, territorial planning through MSF can constitute a double-edged sword. Advancing certain goals, strengthening certain land use rights and benefiting certain actors can come at the expense of others, with the potential to challenge power asymmetries and/or merely reproduce them. My research analyzes the capacities and challenges of MSF to promote balanced power relations, collaboration and a sustainable development, comparatively in two Brazilian states with very different contexts and history; Acre and Mato Grosso. I give a closer look to the state-level "Ecological-Economic Zoning" (ZEE) commissions of Acre and Mato Grosso, and to the implications of MSF and ZEE commissions for indigenous and traditional populations. I do so, acknowledging that power can be used by elites for coercion, but also as a transformative, empowering force for historically marginalized groups. Based on mixed methods, perceptions and empirical evidence are captured applying different data collection instruments to informants of different types, genders, levels and sectors. I conclude that MSF may promote collaboration, balance power relations, empower indigenous peoples and advance sustainable development, but not necessarily. MSF and territorial planning are not technical but rather highly political processes. Particularly, MSF cannot fully represent the inherent diversity of indigenous and traditional populations nor fully ensure their effective participation. MSF have better chances to achieve their goals when they emerge from (and are nourished by) local social movements and shared values, rather than from external demands and institutions in highly polarized contexts. Where sectors are diverse and values are aligned, power differences can become an incentive to collaborate. Moreover, not only economically and/or politically powerful actors but a diversity of actors can influence processes and results (and thus, shape reality), using different forms of power. Finally, MSF do not operate in a vacuum; additional governance mechanisms utilized by different actors deeply shape the power of MSF and equity and effectiveness beyond MSF.